Migrating code using InternalStore

This article describes how a Carmenta Engine 4.x application that uses InternalStore objects should be modified to run correctly using the new MemoryDataSet class.

For more details about the new threading model see Carmenta Engine Threading Model.

Explicit locking

The new MemoryDataSet class requires application code to explicitly lock a MemoryDataSet while it, or any Feature it contains, are being modified. This requires additional code in an application compared to a Carmenta Engine 4.x application but it has two significant benefits:

A MemoryDataSet can be used safely in a TileLayer or GlobeTileLayer that load data in a background thread. This is not possible in Carmenta Engine 4.x because while an InternalStore is protected by a lock there is no way to synchronize access to the GeoObject instances inside the InternalStore.
Since the MemoryDataSet is locked explicitly it can be locked for a sequence of operations which makes it more efficient when inserting, removing or updating more than one Feature at a time.

A consequence of this is that you must add explicit locking to any code that:

Add features to a MemoryDataSet.
Remove features from a MemoryDataSet.
Modify any part of a feature that has been inserted into a MemoryDataSet, this includes changing its geometry, attributes or bounds related properties.
Custom tools that perform any of the actions listed above. All predefined tools work correctly.

A MemoryDataSet is locked by creating a Guard and passing the data set you want to lock as an argument to the constructor. The MemoryDataSet remains locked until the Guard instance is disposed or destroyed.

The modifications will look something like this:

C# - Carmenta Engine 4.x

// Add a new point an InternalStore
Point p = new Point();
p.Set(0, 0, 0);
GeoPoint geoPoint = new GeoPoint();
geoPoint.Create((DataSet)internalStore, p);

// Update position and timestamp attribute at some other point in the application
geoPoint.Point = newPos;
AttributeSet attrs = geoPoint.Attributes;
attrs["TIME"] = DateTime.Now.ToString();
geoPoint.Attributes = attrs;

C# - Explicit locking in Carmenta Engine 5

// Add a new point feature to a MemoryDataSet 
Feature f = new Feature(new PointGeometry(0, 0), Crs.Wgs84LongLat);
using (Guard g = new Guard(memoryDataSet))
	memoryDataSet.Insert(f);
	
// Update position and timestamp attribute at some other point in the application
using (Guard g = new Guard(memoryDataSet))
{
	((PointGeometry)f.Geometry).Point = newPos;
	f.Attributes["TIME"] = DateTime.Now.ToString();
}

For more information see the documentation for the MemoryDataSet and Guard classes.

Migrating code using InternalStore

This article describes how a Carmenta Engine 4.x application that uses InternalStore objects should be modified to run correctly using the new MemoryDataSet class.

For more details about the new threading model see Carmenta Engine Threading Model.

Explicit locking

A MemoryDataSet can be used safely in a TileLayer or GlobeTileLayer that load data in a background thread. This is not possible in Carmenta Engine 4.x because while an InternalStore is protected by a lock there is no way to synchronize access to the GeoObject instances inside the InternalStore.
Since the MemoryDataSet is locked explicitly it can be locked for a sequence of operations which makes it more efficient when inserting, removing or updating more than one Feature at a time.

A consequence of this is that you must add explicit locking to any code that:

Add features to a MemoryDataSet.
Remove features from a MemoryDataSet.
Modify any part of a feature that has been inserted into a MemoryDataSet, this includes changing its geometry, attributes or bounds related properties.
Custom tools that perform any of the actions listed above. All predefined tools work correctly.

The modifications will look something like this:

C# - Carmenta Engine 4.x

// Add a new point an InternalStore
Point p = new Point();
p.Set(0, 0, 0);
GeoPoint geoPoint = new GeoPoint();
geoPoint.Create((DataSet)internalStore, p);

// Update position and timestamp attribute at some other point in the application
geoPoint.Point = newPos;
AttributeSet attrs = geoPoint.Attributes;
attrs["TIME"] = DateTime.Now.ToString();
geoPoint.Attributes = attrs;

C# - Explicit locking in Carmenta Engine 5

// Add a new point feature to a MemoryDataSet 
Feature f = new Feature(new PointGeometry(0, 0), Crs.Wgs84LongLat);
using (Guard g = new Guard(memoryDataSet))
	memoryDataSet.Insert(f);
	
// Update position and timestamp attribute at some other point in the application
using (Guard g = new Guard(memoryDataSet))
{
	((PointGeometry)f.Geometry).Point = newPos;
	f.Attributes["TIME"] = DateTime.Now.ToString();
}

For more information see the documentation for the MemoryDataSet and Guard classes.

Migrating code using InternalStore

This article describes how a Carmenta Engine 4.x application that uses InternalStore objects should be modified to run correctly using the new MemoryDataSet class.

For more details about the new threading model see Carmenta Engine Threading Model.

Explicit locking

A MemoryDataSet can be used safely in a TileLayer or GlobeTileLayer that load data in a background thread. This is not possible in Carmenta Engine 4.x because while an InternalStore is protected by a lock there is no way to synchronize access to the GeoObject instances inside the InternalStore.
Since the MemoryDataSet is locked explicitly it can be locked for a sequence of operations which makes it more efficient when inserting, removing or updating more than one Feature at a time.

A consequence of this is that you must add explicit locking to any code that:

Add features to a MemoryDataSet.
Remove features from a MemoryDataSet.
Modify any part of a feature that has been inserted into a MemoryDataSet, this includes changing its geometry, attributes or bounds related properties.
Custom tools that perform any of the actions listed above. All predefined tools work correctly.

The modifications will look something like this:

C# - Carmenta Engine 4.x

// Add a new point an InternalStore
Point p = new Point();
p.Set(0, 0, 0);
GeoPoint geoPoint = new GeoPoint();
geoPoint.Create((DataSet)internalStore, p);

// Update position and timestamp attribute at some other point in the application
geoPoint.Point = newPos;
AttributeSet attrs = geoPoint.Attributes;
attrs["TIME"] = DateTime.Now.ToString();
geoPoint.Attributes = attrs;

C# - Explicit locking in Carmenta Engine 5

// Add a new point feature to a MemoryDataSet 
Feature f = new Feature(new PointGeometry(0, 0), Crs.Wgs84LongLat);
using (Guard g = new Guard(memoryDataSet))
	memoryDataSet.Insert(f);
	
// Update position and timestamp attribute at some other point in the application
using (Guard g = new Guard(memoryDataSet))
{
	((PointGeometry)f.Geometry).Point = newPos;
	f.Attributes["TIME"] = DateTime.Now.ToString();
}

For more information see the documentation for the MemoryDataSet and Guard classes.

Migrating code using InternalStore

This article describes how a Carmenta Engine 4.x application that uses InternalStore objects should be modified to run correctly using the new MemoryDataSet class.

For more details about the new threading model see Carmenta Engine Threading Model.

Explicit locking

A MemoryDataSet can be used safely in a TileLayer or GlobeTileLayer that load data in a background thread. This is not possible in Carmenta Engine 4.x because while an InternalStore is protected by a lock there is no way to synchronize access to the GeoObject instances inside the InternalStore.
Since the MemoryDataSet is locked explicitly it can be locked for a sequence of operations which makes it more efficient when inserting, removing or updating more than one Feature at a time.

A consequence of this is that you must add explicit locking to any code that:

Add features to a MemoryDataSet.
Remove features from a MemoryDataSet.
Modify any part of a feature that has been inserted into a MemoryDataSet, this includes changing its geometry, attributes or bounds related properties.
Custom tools that perform any of the actions listed above. All predefined tools work correctly.

The modifications will look something like this:

C# - Carmenta Engine 4.x

// Add a new point an InternalStore
Point p = new Point();
p.Set(0, 0, 0);
GeoPoint geoPoint = new GeoPoint();
geoPoint.Create((DataSet)internalStore, p);

// Update position and timestamp attribute at some other point in the application
geoPoint.Point = newPos;
AttributeSet attrs = geoPoint.Attributes;
attrs["TIME"] = DateTime.Now.ToString();
geoPoint.Attributes = attrs;

C# - Explicit locking in Carmenta Engine 5

// Add a new point feature to a MemoryDataSet 
Feature f = new Feature(new PointGeometry(0, 0), Crs.Wgs84LongLat);
using (Guard g = new Guard(memoryDataSet))
	memoryDataSet.Insert(f);
	
// Update position and timestamp attribute at some other point in the application
using (Guard g = new Guard(memoryDataSet))
{
	((PointGeometry)f.Geometry).Point = newPos;
	f.Attributes["TIME"] = DateTime.Now.ToString();
}

For more information see the documentation for the MemoryDataSet and Guard classes.

Migrating code using InternalStore

In this article

Explicit locking

See Also

Reference

Other Resources

Migrating code using InternalStore

In this article

Explicit locking

See Also

Reference

Other Resources

Migrating code using InternalStore

In this article

Explicit locking

See Also

Reference

Other Resources

Migrating code using InternalStore

In this article

Explicit locking

See Also

Reference

Other Resources